1. Field of the Invention
This invention relates to a discharged sheet stacking apparatus on which sheets are stacked, and an image forming apparatus provided with this discharged sheet stacking apparatus in an image forming apparatus main body. Particularly, the invention relates to an image forming apparatus provided with a discharged sheet stacking apparatus designed such that when an ambient member is moved, a discharged sheet stacking tray does not abut against the member in an image forming apparatus.
2. Related Background Art
Heretofore, many image forming apparatuses, such as copying machines, printers, facsimile apparatuses and those combination machines thereof, have been designed such that sheets on which images have been formed (printed) are stacked on a discharged sheet stacking apparatus provided downstream of the discharge port of the image forming apparatus.
Among such image forming apparatuses, there is one of a type in which a sheet discharged from the discharge port of the image forming apparatus is received by and stacked on a discharged sheet stacking apparatus. Also, recently, there have appeared in the market of image forming apparatuses, in order to reduce the footprint for space saving, a discharge sheet stacking apparatus that is positioned on the upper portion of the main body of the image forming apparatus and a sheet discharged from a sheet discharge port on the image forming apparatus side located on the upper surface of the discharged sheet stacking apparatus is received by and stacked on the discharged sheet stacking apparatus. Also, regarding the same problem of footprint, image forming apparatuses of a tall type, which are slim and tall as a whole and which have a great deal of sheet supplying options for supplying a great deal of sheets, is disposed on the lower layer of an image forming apparatus main body.
The footprint refers to a floor area occupied by a printer. That is, it refers to an installation area. As regards the footprint, it is a matter of course that if discharged sheets are placed not on a floor but on the upper portion of the main body of the printer, the installation area as a system decreases.
Now, many of these image forming apparatuses are of a type, in which when, for example, a toner cartridge is to be interchanged, a cartridge cover provided on the upper surface of the image forming apparatus is opened to thereby interchange the toner cartridge from above. Also, in order to improve operability, some of them are such that the cartridge cover has the operating portion of the image forming apparatus.
In the image forming apparatuses of these types, however, it is sometimes the case that when a cartridge cover has been opened, the cover strikes against the discharged sheet stacking apparatus disposed on the upper portion of the image forming apparatus and it is difficult to interchange a toner cartridge. Also, when the cover is opened by force, the cover may strike against the discharged sheet stacking tray of the discharged sheet stacking apparatus, whereby the discharged sheet stacking tray and the cover may be damaged. Also, an operating portion provided on the cartridge cover may strike against the discharged sheet stacking tray of the discharged sheet stacking apparatus to thereby push an operating button by mistake, whereby the printer may be wrongly operated. Also, in some cases, the discharged sheet stacking tray may collide against the operating portion to thereby damage a liquid crystal panel provided in the operating portion.
So, it is conceivable to detach the whole of the discharged sheet stacking apparatus or the discharged sheet stacking tray during the interchange of the cartridge, but this is cumbersome to a user. Or, if the space in which the cover is pivotally moved is sufficiently secured, the position at which the discharged sheet stacking tray is mounted with respect to the image forming apparatus main body must be made high and the discharged sheet stacking apparatus must be disposed on the image forming apparatus main body, and now that image forming apparatuses of a tall type are increased, the height of the entire image forming apparatus becomes great and it may become difficult for the user to use the discharged sheet stacking apparatus.
A similar problem has also arisen in an image forming apparatus provided with a door for maintenance provided on the upper surface of the image forming apparatus and adapted to be opened and closed when jam treatment or maintenance management is done.